Safety razor with operating knob and stop arrangement



April 16, 1968 R. P. MORE 3,37

SAFETY RAZOR WITH OPERATING KNOB AND STOP ARRANGEMENT Filed March 9, 1967 2 Sheets-Sheet 1 II I 52 l 56 50 l 53 I /-/l I 1 LIZ l l m I I ili .W 2

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M i ATT'YS United States Patent 3,377,701 SAFETY RAZOR WITH OPERATING KNOB AND STOP ARRANGEMENT Robert P. More, Trumbull, Conn assignor to Ever-sharp, Inc., Milford, Conn., a corporation of Delaware Filed Mar. 9, 1967, Ser. No. 621,889 6 Claims. (Cl. 30-605) ABSTRACT OF THE DISCLOSURE Safety razor having stops on the blade seat to cooperate with stops on spider assembly to limit upward movement of the stem and the extent to which the operating knob can be unscrewed. Eliminates riveting a stop on spider stem and permits the operating knob to be formed with a closed bottom and permits relaxation of tolerances in manufacturing. A two part operating knob having a closed bottom and which is assembled by pressing the parts together is also shown.

The present invention relates to improvements in safety razors in general and, more specifically, is directed to a new and improved safety razor design having constructional features permitting economical manufacture and assembly.

Safety razors of the double edge type are well known, as is evidenced by the occupied state of the art. Nonetheless, safety razors of this general type have been the subject of considerable research and development over the years, which has served to perfect the art to a very high degree. Notwithstanding this state of development, there remains ample room for improvement, particularly in the area of reducing the cost of the finished product, for it is generally conceded by those working in the field that manufacture and sale of the razor results in a small profit, when contrasted with that obtained from the sale of the blades.

The present invention is directed to a new and improved safety razor design capable of economical manufacture and assembly. Even though the present razor design is a precise instrument, as is required for good shaving, certain dimensional controls may be relaxed in the manufacture of certain of the parts without affecting the overall accuracy and precision of the finished product. Certain parts have been eliminated entirely from the design while other parts have been modified to a certain degree to facilitate easy assembly. Revision of the sequence of assembly of the razor parts is permitted with the present design, which further contributes to a reduction in assembly costs with the obvious effect on the cost of the finished razor. Accordingly, it is contemplated that the present design may be produced and sold with a greater margin of profit than comparable designs of equal quality presently available on the market.

It is, therefore, an object of this invention to provide a new and improved safety razor which is economical to manufacture and assemble.

It is a further object of this invention to provide a safety razor having a novel stop arrangement which permits the parts forming the razor to be made with greater latitude in the manufacturing tolerances without affecting the accuracy of the finished product.

It is a still further object of this invention to provide a novel operating knob construction particularly adapted for use in safety razors.

It is a still further object of this invention to provide a novel stop arrangement which cooperates with an operating knob to eliminate the former need for a stop on the lower end of the spider and stem, thus permitting revision of the assembly sequence.

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It is a still further object of this invention to provide a safety razor design which is more easily assembled when contrasted with prior art designs.

Other objects other than those specifically set forth will become apparent when reference is made to the following description and accompanying drawings illustrating a preferred embodiment.

FIGURE 1 illustrates an exploded perspective view of the parts forming the safety razor of the present invention;

FIGURE 2 is an enlarged, partly sectioned view of an insert for the operating knob;

FIGURE 3 is a cross-sectional view of the operating knob which receives the insert shown in FIGURE 2;

FIGURE 4 is a crosssectional view of the insert and operating knob assembled with a portion of the insert shown in full elevation; and

FIGURE 5 is a fragmentary elevational view of the razor shown in FIGURE 1 after assembly with the sectional caps in the fully opened position and parts in section to illustrate the stops and the relation of the operating knob and stem.

The parts forming the safety razor are illustrated generally by reference numeral in FIGURE 1. These include a pair of sectional caps 11 and 12 which are mounted on a center bar 13 through the provision of cross braces 14 and 15. The detailed constructional features of the center bar 13 and cross braces 14 and 15 are disclosed in copending application Ser. No. 618,789, filed Feb. 27, 1967.

The center bar 13 is carried at the upper end of a spider stem 16 which is threaded at the lower end as indicated by reference character 17. The attachment of the spider stem 16 to the center bar 13 is fully described in copending application Ser. No. 621,888, filed Mar. 9, 1967 and reference is made to that application, if necessary, to understand the present invention. While a polygonal spider stem 16 and single ply center bar 13 is illustrated, it is apparent that other types of stems and multiply center bars may be used.

A handle subassembly is indicated generally at 20 and includes a tubular handle member 211, having a blade seat 22 mounted at the upper end by means of an annular metal neck or collar 23 which is riveted as at 24 to overlie an opening formed in the blade seat 22. The blade seat 22 is of conventional design and at its outer margins includes guard bar portions 25 and 26 which are adapted to contact the shavers skin to tension the same for smooth shaving. The central portion of the blade seat 22 is provided with a pair of slots 27 and 28 at opposite ends which are adapted to receive downwardly projecting arms 29 and 36 formed at the ends of the center bar 13.

The lower end of the handle 21 is of reduced diametar as at 31 and terminates in an annular collar 32 of increased diameter, serving a function to become ap' parent. A knob insert 33 is adapted for attachment to the handle and is provided with internal threads 34 which co-operate with the threads 17 on the end of the spider stem 16. The threads illustrated are a modified form of buttress thread, however, other types may be used with good results. The insert 33 may be formed of any suitable material and, in the preferred embodiment is formed of easily worked metal, such as brass, and subsequently plated. An operating knob 35 may be formed of plastic or the like and is provided with longitudinally extending ribs 36 which facilitate gripping by the user of the razor to impart rotation to the insert 33, causing the spider stem 16 to shift axially in a manner to become apparent.

Each of the cross braces 14 and 15 includes axially extending tab members 40 and 41, 42 and 43, respectively. The tabs are designed for interlocking with a center bar 13 1) to hold the sectional caps 11 and 12 in pivoting relation on the center bar in a manner well known.

The slots 27 and 28 at opposite ends of the blade seat 22 are of sufficient width to pass the upper tabs 4% and 42, but are narrow enough to preclude the passage of the lowermost tabs 4-1 and 43, thus limiting upward movement of the spider stern. At opposite ends of the blade seat 22, along opposite sides of the slots 27 and 28, a portion of the blade seat is deformed downwardly, as indicated at 44 and 45 for the slot 27, and 46 and 47 for the slot 28. The deformed portions are formed in the manufacture of the blade seat prior to plating and, as will become apparent in the description of FIGURE 5, cooperate with the lower tabs 41 and 43 on the cross braces to form stops to limit the upward movement of the spider stem 16.

Referring now to FIGURE 2, the insert 33 is provided with an internal bore 50 which is connected by a radial shoulder 51 to the threaded bore 34. A shoulder 52 is formed at the outer end of the bore and merges with a circumferential portion 53 of reduced diameter which, in turn, merges with an outwardly flowing frustoconical guide portion 54 which serves as a locating guide in assembly of the knob to the handle 21. The outer contour of the insert 33 is of stepped configuration having an annular collar 55 at the upper end, a circumferential portion 56 of reduced diameter and a portion 57 of further reduced diameter which is knurled as at 58.

As seen in FIGURE 3, the operating knob 35 is provided with a tapered bore 66 which merges through an outwardly flaring section 61 into a radial shoulder 62 which terminates in an enlarged bore 63. The knob is sized so as to receive the insert 33 with a snug fit. The lower end of the tapered bore 60 is closed off by a continuous wall portion 64 which is integral with the remainder of the knob to provide a smooth, uninterrupted end on the knob 35. The taper of the bore 60 is extremely slight and may be of the order of approximately one degree (1) to assure that the insert 33 will be properly located when it is pressed therein.

The relationship of the insert 33 to the knob 35 after assembly is illustrated in IGURE 4. The annular collar 55 on the insert serves to trim the upper end of the knob while the circumferential portion 56 is snugly received in the bore 63. The knurled portion 58 of the portion of reduced diameter 57 on the insert 33 bites into the wall of the tapered bore 6% to assure that relative rotation will not occur between the insert and the knob. The closed end wall 64 on the operating knob 35 prevents the ingress of foreign matter which can interfere with the smooth action between the threads 34 on the insert and cooperating threads 17 on the spider stem 16.

The steps of assembling the razor consist of positioning the insert 33 over the lower end of the handle 21 such that the shoulder 52 is interlocked with the shoulder formed on the collar 32. This permits rotation of the insert relative to the handle while precluding relative axial movement. The operating knob 35 may be assembled to the insert prior to assembly to the handle or after the insert 33 is positioned on the handle.

The spider stem 16 is joined to the center bar 13 in the manner noted above and this subassernbly is positioned with the stem 16 in the annular bore 70 through the handle 21 and the arms 29 and in the slots 27 and 23. The knob is rotated a few turns so as to intermesh the threads 17 on the stem with the threads 34 on the insert 33 and, at this time, the arms 29 and 30 will be drawn down into the slots 27 and 28 of the blade seat. The sectional caps 11 and 12 are held in a suitable fixture in parallel relation to the center bar 13 and the cross braces 14 and 15 are advanced toward the ends of the center bar 13 with the pivot pins on the ends of the cross braces aligned with and entering openings formed in the sectional caps simultaneously with the tabs 43 being interlocked with suitable locking means on the center bar 13. At assembly, the lower tabs 41 and 43 on the cross braces 14 and 15 are positioned below the blade seat 22 to a greater extent than shown in FIG- URE 5.

When the cross braces 14 and 15 are interlocked with the center bar 13, the stem 16 may not be unthreaded from the knob as the upward movement of the stem 16 is limited by engagement of the lower tabs 41 and 43 with the stops 4-4 and 45, and 45 and 47, respectively. Also, the stops are dimensioned to prevent the sectional caps 11 and 12 from opening beyond a point where they would not return properly when the stem is retracted. As noted previously, the upper tabs 4-53 and 42 are of reduced width to permit passage through the slots 27 and 23 formed in opposite ends of the blade seat 25 to permit the stem 16 to be retracted for clamping a razor blade on the seat 22.

It can be appreciated that the novel razor construction permits the razor parts to be expediently assembled. For example, the metal insert 33 is, merely pressed into the plastic operating knob 35. The insert 33 is installed by pressing the portions of reduced diameter into the complementary shaped bores of the plastic operating knob. The stops on the blade seat may be formed during the manufacture of the blade seat, and become operative upon assembly of the razor parts. It is to be appreciated that an equivalent form of stop means can be provided on other types of center bars, for example, if the center bar is two-ply, the stop can be formed by spreading the lower part of the ply, deforming a part of the arm on the center bar, or the equivalent. This may be accomplished before or after assembly, depending on the constructional features of the razor.

Locating the stop means on the blade seat and upper part of the spider assembly permits relaxation of manufacturing tolerances on the spider stern length. Moreover, the present arrangement does away with the conventional rivet washer on the lower end of the stern and riveting operation of the prior art which provided a stop to limit the upward movement of the stem 15. In former designs, a trim cap or trim plate was provided to close off the end of the operating knob after the riveting operation had been completed. In the present design, this is eliminated, as the operating knob is formed with a solid integral end wall which precludes the entry of foreign matter which can impair the smooth operation of the threaded insert on the stem 16. More importantly, however, the elimination of the essential step of staking or riveting the lower end of the stem and subsequent installation of a trim cap reduces the cost of manufacture.

Upon a consideration of the foregoing, it will become obvious to those skilled in the art that various modifications may be made without departing from the invention embodied herein. Therefore, only such limitations should be imposed as are indicated by the spirit and scope of the appended claims.

I claim:

1. In a safety razor of the type wherein a spider assembly is mounted in a handle having a blade seat, said spider assembly including sectional caps carried on a shiftable spider stem through the provision of a center bar and cross braces for opening and closing movements to clamp a razor blade on said blade seat, the improvement comprising knob means mounted for rotation on said handle and held against axial movement relative thereto, said knob means threadably receiving one end of said spider stem, and stop means formed on said spider assembly for engagement with co-operatin g stop means on said blade seat to limit the upward movement of said spider stem and thereby preclude disengagement of said knob means from said stem while simultaneously preventing said sectional caps from opening beyond a point where they can be returned to the blade clamping position by reversing the rotation of said knob means.

2. The improvement in safety razors of claim 1 wherein said knob means includes an insert threadably receiving said stem, said insert being received in an operating knob having an integral closed bottom to cover the end of said stem.

3. The improvement in safety razors of claim 1 wherein said step means formed on said spider assembly comprises tab means forming a part of said cross brace and said co-operating stop means on said blade seat comprises deforming a part of said blade seat downward toward said handle in axial alignment with a part of said tab means.

4. A safety razor comprising in combination, a handle having a stem receiving 'bore, a spider stem positioned in said handle, center bar means on one end of said stem, said center bar means mounting sectional caps for opening and closing movement relative to a blade seat, kno'b means threadably mounted on another end of said stem, means joining said knob means to said handle to prevent movement axially thereof While permitting free rotation relative to said handle whereby said spider stems may be shifted axially of said handle by rotation of said knob means thereby opening and closing said sectional caps, and stop means carried on said center bar means and engageable with said blade seat to limit opening of said sectional caps and rotational movement of said knob means thereby preventing disengagement from said spider stem.

5. The safety r-azor of claim 4 wherein said knob means includes an insert threada'bly received on said stem, said insert being received in an operating knob having a closed bottom to cover the end of said stem and means to prevent relative rotation between said operating knob and said insert.

6. The safety razor of claim 4 wherein said stop means on said center bar means comprises tab means formed on cross braces carried at opposite ends of said center bar and projecting laterally therefrom, said tab means being engageable with said blade seat to limit the upward movement of said stem.

References Cited UNITED STATES PATENTS 1,918,227 7/ 1933 Muros -605 1,960,290 5/ 1934 Stoney 30-605 2,048,559 7/ 1936 Muros 30-60.5 2,748,467 6 /1956 Shnitzler et al 30-60.5 2,766,522 10/1956 Linzmeyer et al. 30-60.5

MYRON C. KRUSE, Primary Examiner. 

